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Discussion Starter · #1 ·
So how do you guys figure out how much power you are applying to your sub? On other forums I see people talking about how many volts they are driving the sub with.

The reason I ask is that I am going to be playing around with a couple of Anarchy drivers in a couple of different configurations and the amp I plan to use can deliver a lot more power than these drivers can handle.

I don't want to blow up these little beasts.
 

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Measuring the voltage is about as close as you can easily get at home.

I wouldn't worry unduly about damaging the drivers; with modern units like the Exoduses it will take insensitivity on your part (not paying attention to the drivers making inappropriate noises) or a desire to inflict damage to harm them. With actual music/movie content the peak to average ratio means they won't heat up all that much, likely not enough to damage the coils, but what will most likely cause damage is over excursion. Pay attention to this during testing and use and you'll be fine. If in doubt, back it off a bit. You could also face the drivers upwards during testing, and make a cardboard bridge over the driver, cut so that it doesn't interfere with the surround and the cone touches it at Xmax; if it doesn't touch, great and if it does, you'll know when you've reached the driver's limit.

I've used kW amps to power my vintage Celestion 15W speakers without damage because I back off when they start to sound unhappy.
 

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Discussion Starter · #4 ·
Thanks gents. I'm an electronics dummy so you will have to bear with me. So I can use my el cheapo voltage meter to do this?

Its over excursion that I am worried about. I just don't want to do something foolish the first time I fire the drivers up.
 

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So how do you guys figure out how much power you are applying to your sub? On other forums I see people talking about how many volts they are driving the sub with.
What they’re talking about is the voltage from their receiver’s subwoofer output jack being enough to drive the outboard amp. This is typically only something like 1-4 volts.


The reason I ask is that I am going to be playing around with a couple of Anarchy drivers in a couple of different configurations and the amp I plan to use can deliver a lot more power than these drivers can handle.

I don't want to blow up these little beasts.
Just start out with the amp’s gains set really low. Or if the amp doesn’t have any gains, start with the receiver’s sub out set low.

Regards,
Wayne
 

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Thanks gents. I'm an electronics dummy so you will have to bear with me. So I can use my el cheapo voltage meter to do this?
You can with a sine or pink noise as the source, but not with a dynamic signal. DVM's use a different type of ADC which is quite slow and will always be lagging behind typical 'content' signals. For that, a resistive divider to drop the signal to a low enough level for your soundcard input and a scope program would work better.

Its over excursion that I am worried about. I just don't want to do something foolish the first time I fire the drivers up.
Relax, The only way you'll damage drivers on initial fire up is if you have the signal levels maxxed out and start to play from the middle of a track. Bring it up slowly and listen for the driver to start to sound strained and/or use my cardboard Xmax indicator. Drivers aren't like fuses that go 'pop' very easily.
 

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I think the OP means that people will refer to the sub getting say 30 volts from the amp. This then translates into watts, and can be check with a resistor on the lead from the amp thats the same impedence as your sub. Or something along these lines..... i have been looking for more info on this as well. People use this to see what their amp is actually putting to the sub, and could be very usefull if someone on here know more about how to do this properly.
I believe you run sine wave or pinknoise, turn the amp to clipping and back down. remove the sub from the wire and attatch the resistor. Then check the voltage at the resistor with the amp playing pink noise (or sine wave) at the same volume you had right below clipping. Then the voltage you get can be changed to volts....
Is this correct or am i missing something?
 
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